Loom let-off mechanism



July 26, 1960 1. B. M KEOWN 2,94,352

LOOM LET-OFF MECHANISM Filed April 13, 1959 3 Sheets-Sheet 1 3 IRMA B.MEKEowN ATTORNEYS INVENTOR.

July 26, 1960 I. B. M KEOWN 2, 4 5

LOOM LET-OFF MECHANISM Filed April 13, 1959 3 Sheets-Sheet 2 him 5.MEKEOWN BY w, mw+ W ATTORNEYS Juiy 1. s. MCKEOWN 2,946,352

LOOM LET-OFF MECHANISM Filed April 15, 1959 3 Sheets-Sheet 3 INVENTOR:IRMA B M KEowN 2; B finazmmw-m k ATTORNEYS Patented July 26, 1960 1.00MLET-OFF MECHANISM Irma B. McKeown, PA). Box 5091, Charlotte 6, N.C.

Filed Apr. 13, 1959, Ser. No. 806,125

4 Claims. ((11. 139-110) This invention relates generally toimprovements in loom let-off mechanisms and more particularly to aletoff mechanism adapted to rotate the Warp beam and let 01f the yarn ata rate which corresponds to the rate at which the woven cloth is takenup.

In the weaving of cloth, it is desirable to feed the warp yarns at thesame rate of speed that the cloth is taken up while maintaining the warpyarns under equal tension at all times. There have been many let-offdevices employed, all of which were striving, by one means or another,to maintain the warp yarns under equal tension while feeding the yarnsat a rate corresponding to the rateof production of the cloth.

Generally, there are two warp let-off systems presently employed. In onesystem, the warp yarns are let off or unwound from the warp beam inaccordance with the amount of friction applied to a brake drumassociated with the warp beam. In the other system, the warp beam isrotated in a step-by-step intermittent manner by a mechanism which iscontrolled by the tension of the warp yarns. In the latter system, thewarp beam is intermittently rotated in equal steps by means of a ratchetand pawl arrangement which is drivingly connected to a large gear on oneend of the warp beam. In this system, the step-by-step rotation of thewarp beam is controlled by movement of a whip roll over which the warpyarns pass and the whip roll is operatively connected with the pawl andratchet. Thus, each step of rotation of the warp beam is the same lengthand corresponds to the spacing between the teeth of the ratchet. .Withthis system, each time the pawl and ratchet mechanism is operated thewarp beam lets off a fixed amount of yarn when the tension of the yarnsreaches a predetermined amount. This type of let-off does not feed thewarp yarn in amounts which correspond to the demands of the weavingoperation since the warp beam is rotated equal amounts with each step.

With the foregoing in mind, it is the primary object of this inventionto provide an improved let-off mechanism which is responsive to thetension of the warp so that the Warp beam is rotated in intermittentsteps and the yarn is unwound or let off varying amounts which arecommensurate with the amount of tension on the warp yarn to therebymaintain the warp yarns under a more uni form tension than hasheretofore been possible.

It is another object of this invention to provide an improved let-ofimechanism for intermittently rotating the warp beam of a loom by meansof an overriding or oneway clutch mechanism which is interposed betweenthe warp beam driving pinion and the operating components of the loomwhereby the warp beam will be rotated in a step-by-step manner to letoff the warp yarns varying amounts which correspond to the tension ofthe warp yarns,

It is another object of this invention to provide an improved let-ofimechanism for intermittently rotating the warp beam in a step-by-stepmanner in varying amounts and which mechanism is provided with means forreadily 2 engaging and disengaging the let-off mechanism from the warpbeam.

It is a more specific object of this invention to provide an improvedwarp tension controlled let-off mechanism which is of simplifiedconstruction, adapted to be readily installed on existing looms andrequires very little adjustment prior to and during its operation.

Some of the objects of the invention having been stated, other objectswill appear as the description proceeds, when taken in connection withthe accompanying drawings, in which Figure 1 is a fragmentary elevationof the lower righthand rear portion of a loom with portions broken awayfor purposes of clarity and illustrating the improved letoif mechanismof the'present invention associated therewith;

Figure 2 is an enlarged fragmentary vertical sectional view takensubstantially along the line 2--2 in Figure 1, with parts broken away,and illustrating the type of oneway clutch used in connection with theimproved let-ofi mechanism of the'present invention;

' Figure 3 is a fragmentary end elevation, with parts in I section andparts broken away, illustrating the invention associated with afragmentary portion of the rear portion of one end frame and being takensubstantially along the line 3-3 in Figure 1;

Figure 4 is a fragmentary plan view looking downwardly on Figure 1 andin the direction of the line 4-4;

Figure 5 is a horizontal sectional view taken substantially'along theline 5--5 in Figure 1.

Referring to the drawings, the present invention is shown associatedwith a conventional loom having a side frame 10 which supports one endof a warp beamil having a plurality of warp yarns W wound thereon. Thewarp beam 11 is supported on a shaft 13 which is in turn rotatablysupported on a bracket 14 suitably secured to the rear portion of theloom frame iii. The warp beam 1-1 is provided with a relatively largegear 15 which is suitably secured to one end of the warp beam and isutilized to drive the warp beam, in a manner to be later described. Theloom frame 10 also supports a main cam shaft 20 which is a conventionalpart of the drive mechanism of the loom and is driven in timed relationto operation of the loom so that the shaft 20 makes one revolution foreach two picks of the loom.

The loom is also provided with the usual instrumentalities for formingcloth, not shown, whereby with each pick of the loom the warp yarns areseparated by the heddles to form a shed. A filling yarn is inserted inthe open shed and as the warpyarns are again joined and the lay is movedforwardly to beat-up position to move the filling yarn into position toform another pick of the woven cloth. The loom is'also provided with asuitable cloth take-up roll, not shown, which maintains the cloth andwarp yarns under tension and'takes up the cloth as it is formed.Movement of the take-up roll is controlled in timed relation tooperation of the loom and'the take-up roll is rotated to take up thecloth in a step-by-step manner and in equal increments.

The loom is also provided with a whip roll 25 (Figures 1 and 4) having asupport shaft 26 extending therefrom and the distal end of which ismounted for rotation in a bearing block 27. The bearing block 27 isremovably supported in the rear end of a bracket 30, the front end ofwhich is fixed on one end of a pivot shaft 31. The pivot shaft 31 ismounted for oscillation in the upper end of a bearing support 32, thelower end of which is fixed on the rear end of a support bracket 33suitably secured at its front end to the loom frame 10. The end ofthepivot shaft 31, opposite the bearing support 30, has one end of a lever35 fixed thereto and the opposite end of the lever 35 has the upper endof a tension spring 36 suitably secured thereto. The lower end of thetension spring 36 is connected to an eye bolt 37 which is mounted forvertical adjustment in the horizontal leg of an angle bracket 40. Theangle bracket 40 is suitably secured to a pivot bracket 41 which is inturn fixed on the side frame (Figure 3).

The warp yarns W are unwound from the warp beam 11 and pass upwardlyandover the whip roll 25, then forwardly through the usual heddles and loomreed, not shown, to join the cloth being woven. The amount of tension inthe warp yarns W determines the vertical position of the whip roll 25since it is mounted in a floating condition and may oscillate withfluctuations in the warp tension. The amount of upward pressure of thewhip roll 25 against the sheet of warp yarns W depends upon the amountof tension in the spring 36 (Figure 3) and the amount of tension in thespring 36 may be varied by adjusting the vertical position of the eyebolt 37.

Thus, when the tension in the warp yarns W is increased, by reason ofthe cloth being taken up, the whip roll 25 will be moved downwardlyslightly against the tension in the spring36. On the other hand, whentension in the warp yarns W is lessened, by reason of the yarns beingunwound from the warp beam, in a manner to be later described, thetension spring 36 will cause the whip roll 25 to be raised. It is to beunderstood that where p the terms greater and lesser tension are used,they do not refer to substantial degrees of variation in the normaltension of the warp yarns but to small degrees of variation in tensionwhich normally occur in the warp yarns when the cloth is taken up andwhen the yarn is let oif of the warp beam.

The improved let-off mechanism of the present invention operates inresponse to small variations of tension in the warp yarns which areindicated by variations in the position of the floating whip roll 25. Itis with the type of loom heretofore described that the present let-offmechanism is preferably associated, but it is to be understood that itmay be applied to other types of looms, if desired. One importantfeature of the present let-oft mechanism resides in the fact that theamount of yarn let off by rotation of the warp beam is always in exactproportion to the amount of tension applied to the sheet of warp yarns Wprior to action of the let-01f mechanism. Thus, when the tension in thewarp yarns increases greatly the improved warp let-off mechanism of thisinvention supplies a greater amount of yarn than it does when the warptension increases only slightly above the amount desired.

In order to transmit any variations in the position of the whip roll 25to the let-off mechanism, the whip roll 25 is operatively connected tothe let-oif mechanism by a composite link broadly indicated at 45. Thelink 45 comprises a sleeve 46, the upper end of which is oscillatablyconnected, as at 47, to the bracket in which one end of the whip roll 25is-rotatably supported. The composite link 45 also includes a controlrod 50 mounted for sliding movement in the sleeve 46 and the upper endof the control rod 50 is threaded to receive a pair of lock nuts 51which seat against the upper end of the sleeve 46 and limit downwardmovement of the control rod 50. The lower end of the control rod 50extends downwardly beyond the lower end of the sleeve 46 and isoscillatably connected to the medial portion of an actuating lever '55.A compression spring 60 surrounds the control rod 50 and its upper endbears against a washer which is seated against the lower end of thesleeve 46 while its lower end bears against a washer which is seatedagainst a pair of lock nuts 61 threadably mounted for longitudinaladjustment along the control rod 50. The spring 60 normally holds thecontrol rod 50 in its lowermost position relative to the sleeve 46 andthe lock nuts 51 may be rotated to increase or decrease the effectivelength of the composite link 45.

. The forward end of the actuating lever -55 is provided with a camroller 64 which is in vertical alinenient with an actuating cam 65suitably secured to the main cam shaft 20. The rear end of the actuatinglever 55 is fixed to the upper horizontal portion of a clutch housing inwhich the outer element 71 of an overriding or one-way clutch broadlyindicated at 72 is mounted. In this instance, the outer element 71 isformed of a hardened steel sleeve which is clampingly held in a fixedposition in the housing 70 by a screw 73 (Figure 2). The oneway clutch72 also includes an inner element 74 which is provided with a pluralityof cam openings 75, each of which is provided with a roller 76. It willbe noted in Figure 2 that the bottoms of the openings 75 are cut at anangle and the rollers 76 are urged into engagement with the outerelement 71 and the bottoms of the openings 75 by compression springs 77.

When the free or operating end of the actuating lever 55 (Figure 3) israised, the clutch housing 70 and outer element 71 are rotated in acounterclockwise direction so that the rollers 76 are wedged between theouter and inner elements 71 and 74 and transmit the rotational motion toa let-off shaft 80 to which the inner element 74 is keyed. On the otherhand, when the free end of the actuating lever 55 is lowered, the clutchhousing 70 and outer element are rotated in a clockwise direction sothat the rollers 76 are not wedged between the outer and inner elements71 and 74. Thus, when counterclockwise rotation is irnparted to theclutch housing 70, the shaft 80 will be rotated in a counterclockwisedirection but when clockwise rotation is imparted to the clutch housing70 the shaft 80 will not rotate.

Referring to Figure l, it will be noted that the medial portion of theshaft 80 is mounted for rotation in an eccentric sleeve 82 which issupported adjacent opposite ends in bearing members 83 and 84. Thebearing member 83 is suitably secured to the side frame of the loom 10(Figure 3) and the bearing member 84 is suitably supported on oneupstanding leg of a substantially U-shaped support casting 85 (Figurel). The horizontal portion of the casting 85 is fixed to an outwardlyextending portion of the side frame 10 while the other upstanding leg issuitably fixed to the side frame 10.

The eccentric sleeve 82 (Figures 1 and 5) has an enlarged boss or hubformed integral with the central portion thereof and the hub 90 has oneend of a lever 91 fixed thereto or formed integrally therewith. The freeend of the lever 91 has the lower end of a link 92 oscillatablyconnected thereto as at 93 (Figure 3) and the upper end of the link 92is oscillatably connected, as at 94, to the medial portion of a handlever 96. The lower end of the hand lever 96 is oscillatably mounted asat 97 on the rear end of the bracket 41, heretofore described. When thehand lever 96 is positioned as shown in Figure 3, it abuts against thehorizontal leg of the angle bracket 40 to prevent rotation of the handlever 96 in a clockwise direction.

The outermost end of the shaft 80 has a brake wheel 100 fixed thereto(Figures 1 and S), the outer periphery of which is engaged by a brakestrap or band 101. One end of the band 101 is suitably secured to asupport 102 fixed in the casting 85 and the other end supports a weightmember 103. The wheel 100 and the brake band 101 thus present a brakingaction to frictionally resist rotation of the shaft 80 in eitherdirection and the amount of frictional resistance depends upon the sizeof the weight member 103. The innermost end of the shaft 80 has adriving pinion 106 fixed thereto (Figures 1 and 5) which is normallypositioned in driving engagement with the gear 15.

In operation, assuming that the warp yarns W are under the desiredamount of tension, the actuating lever 55 will be supported by the whiproll 25 and the composite link 45 so that with rotation of the main camshaft 20 the cam 65 will pass by the cam roller 64 on the forward end ofthe actuating lever 55 without raising the same. Thus, when the free endof the actuating lever 55 is held in a raised position, shaft 80, pinion106 and the warp beam 11 will not be rotated. Of course, the tension inthe warp yarns W will not remain constant because the cloth iscontinually being taken up to thereby increase the tension on the warpyarns W. When the cloth is taken up the tension on the warp yarns W willincrease and lower the whip roll 25. With downward movement of the whiproll 25, the composite link '45 and the free end of the actuating lever55 will also be lowered (Figure 3) in proportion to the amount ofincrease in tension in the warp yarns W.

When the forward end of the lever 55 is lowered, the clutch housing 70will be rotated in a clockwise direction around the inner clutch element74 without imparting any rotation to the shaft 80. Then, as the camshaft 20 rotates the high portion of the cam 65 will engage and raisethe cam roller 64 and the free end of the lever 55 to impartcounterclockwise rotation to the clutch housing 70 (Figure 2). Ascounterclockwise rotation is imparted to the housing 70, the rollers 76will cause this rotation to be imparted to the inner element 74. Thus,the distance the forward end of the actuating lever 55 is lowered willdetermine the amount of movement imparted to the shaft 80 through theclutch 72 when the cam 65 engages the roller 64 to raise the free end ofthe lever '55. As counterclockwise rotation is imparted to the shaft 80(Figure 3), like rotation will be imparted to the pinion 106 to transmita corresponding amount of clockwise rotation to the gear 15 and the warpbeam 11 to let off a corresponding length of warp yarn W. As the warpyarns W are let off, by a step in rotation of the warp beam 11, thetension in the warp yarns W will be decreased thus allowing the tensionspring 36 to raise the whip roll 25 slightly thereby raising the freeend of the actuating lever 55 an amount which corresponds to the amountthe tension in the Warp yarn W is decreased.

The compression spring 60, surrounding the lower end of the control rod50, allows the free end of the actuating lever 55 to be raised by thecam 65 without causing a corresponding rise of the whip roll 25. Whenthe free end of the lever 55 is raised, the compression spring 60 willbe compressed and the control rod 50 will slide upwardly in the sleeve46. The compression spring 60 also returns the control rod 50 to itslowermost position in the sleeve 46 following each engagement of the cam65 with the cam roller 64 on the forward end of the lever 55. The locknuts 51, threadably mounted on the upper end of the control rod 50,provide adjustment means for varying the effective length of thecomposite link 45 to thereby adjust the position of the cam roller 64and the actuating lever 55 relative to the position of the whip roll 25.This adjustment enables the operator to adjust the amount of yarn letoff with a given variation of tension in the warp yarns W.

At times, such as when a break-out occurs in the warp yarns, it isnecessary to slacken the warp yarns and the present let-off mechanismmay be easily released from driving engagement with the warp beam 11. Inorder to release the let-off mechanism, the operator revolves the handle96 (Figure 3) in a counterclockwise direction ap proximately 180degrees, thus moving the same out of engagement with the horizontal legof the angle bracket 40 and lower the connecting link 92 along with theouter end of the lever 91. This movement will revolve the eccentricsleeve 82 and lower the shaft 80 whereby the pinion 106 will move out ofengagement with the relatively large gear 15 carried by the warp beam11. Rotation of the handle 96 will thus completely disengage the warpbeam 11 from the let-off mechanism and the warp beam 11 may then berevolved as desired. In order to again engage the let-off mechanism withthe gear 15 of the warp beam 11, it is merely necessary that an operatorrevolve the handle 96 in a clockwise direction so that it again abutsvagainst the horizontal leg of the angle bracket 40 and the shaft will beraised upwardly so that the pinion 106 again engages the gear 15. I

It is preferred that the let-off mechanism be operated from a cam on themain cam shaft, as illustrated, but it is to be understood that theactuating lever 55 may be operated from other conventional parts of thedrive or other operating mechanisms of the loom which operate in timedrelationship thereto. The let-off mechanism shown operates on alternatepicks of the loom but could be operated on every pick by providing twohigh cam lobes on the cam 65.

The warp let-off mechanism of the present invention is operated inresponse to any variation in the tension of the warp yarns to feed orlet-oif the warp yarns in va1i able amounts, according to the amount ofvariation in tension of the warp yarns. In other words, the greater theincrease in tension of the warp yarns the greater the amount of yarnwhich is let off by the mechanism to thus immediately lessen the tensionin the warp yarns. Any variation of the tension in the warp yarns isimmediately detected and the improved let-off mechanism immediatelyfeeds the correct amount of yarn to correct the tension in the warp sothat the desired tension in the warp yarns may be maintained within avery close range.

In the drawings and specification there has been set forth a preferredembodiment of the invention and, although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation, the scope of the invention being defined in theclaims.

I claim:

1. Ina warp beam let-off for a loom having a frame, a Warp beam withwarp yarns wound thereon, and a movable whip roll over which said warpyarns pass, said whip roll being movable in response to variations inthe tension of said warp yarns; said let-oif comprising a gear carriedby one end of said warp beam, a pinion engaging said gear, an eccentricsleeve oscillatably supported on said frame, a shaft rota-tablysupported in said eccentric sleeve, said pinion being fixed on one endof said shaft, brake means adjacent the other end of said shaft tofrictionally resist rotation of said shaft, a one-way clutch carried bysaid shaft, an actuating lever connected at one end to said clutch,actuator means operable in timed relation to operation of said loom,said actuator means being at times engageable with the other end of saidactuating lever, link means operatively connecting said actuating leverwith said movable whip roll whereby the position of said whip rolldetermines the position of the other end of said actuating lever inrelation to said actuator means, and manually operable means foroscillating said eccentric sleeve to move said pinion into and out ofdriving engagement with said gear.

2. In a let-off for a loom having weaving instrumentalit-ies including awarp beam, warp yarns wound on said warp beam, a whip roll over whichsaid warp yarns pass as they are fed to components of the weavinginstrumentalities of said loom, said whip roll being resilientlysupported and movable in response to variations of tension in said warpyarns; said let-off comprising a gear on one end of said warp beam, aneccentric sleeve oscillatably supported on said loom, a shaft rotatablysupported in said eccentric sleeve, a pinion fixed on one end of saidshaft and engageable with said gear, brake means supported on the otherend of said shaft for friotionally resisting rotation of said shaft, aone-way clutch device carried by said shaft whereby movement of saidclutch device in one direction will cause corresponding movement of saidshaft and movement of said clutch device in the other direction will noteffect movement of said shaft, an actuating lever connected at one endto said oneway clutch, cam means intermittently engageable with theother end of said actuating lever for imparting movement to saidactuating lever in said one direction, a contrQllinkoperativelyconnecting said whip roll and actuating lever for controllingmovement of said actua ling lever insaid other directionto therebycontrol the degree, of movement imparted to said lever in said onediIeQtion, and manuallyoperablemeans for oscillating said eccentricsleeve to thereby selectively move said inion into and out of drivingengagement with said gear.

3. In a structure. according to claim 2 wherein said control linkcomprises a sleeve operatively connected at one end to said Whip roll, arod slidably supported in said sleeve, adjustable stop; means at one endof said rod, said stop means being en gag sflble" with said one. endofsaid sleeve,sand resilient means, carried adjacent the other end; ofsaid rod andengageable. with the other end, of said sleeve. forresiliently urging said step means into engagement with said one end ofsaid sleeve, said other end of said rod being connected, intermediatethe ends of said actuating lever.

4. In a structure according to. claim 2 wherein said manually operablemeans comprises a handle. osciliatably mounted at one end in said frame,a link connected at one end intermediate the ends of said handle, alever connected at one end to said eccentric sleeve, the other end ofsaid link being connected to'the other'end of said lever, and stop meanson said loom engageable with said handle. a

References Cited'in the file of this patent UNITED STATES PATENTSBergstrom June. 3; 19578

